Ethylenic polymers or α-olefin polymers have non-polar molecular structures and insufficient affinities to other substances, and thus it is being attempted to introduce various functional groups to the polymers. For example, the following polymers having functional groups introduced at the terminals have been reported.
(1) A polymer obtained by attaching unsaturated carboxylic acids having 3 to 10 carbon atoms, such as maleic acid, to the terminals of a liquid ethylenic polymer or a liquid α-olefin containing a double bond at one terminal, (for example, JP-B No. 7-78098), a polymer modified by epoxidation of the terminals (for example, JP-B No. 7-91338), a polymer modified by hydroxylation of the terminals (for example, JP-B No. 7-103181);
(2) A polymer resulting from epoxidation, hydroxylation or sulfonation of the terminals of a syndiotactic α-olefin polymer containing a double bond at one terminal (for example, U.S. Pat. No. 5,252,677);
(3) A polymer resulting from hydroxylation-, epoxidation, maleination, sulfonation, silylation or halogenation of a double bond at one end of an ethylenic polymer (for example, JP-A No. 2001-2731 and JP-A No. 2003-73412); and
(4) A halogen-terminated polymer, a carboxyl-terminated polymer, an amino-terminated polymer or the like, derived from a polymer having hydroxyl at one terminal that is obtained by oxidation of a low molecular weight polyethylene (for example, JP-A No. 1-217007).
Among these reported examples, the polymers of groups (1) to (3) are polymers obtained by modification of polymers having double bonds at one terminal. These polymers can be used in various applications, but their application fields are limited because the modification methods are limited, the contents of functional groups may be small depending on the modification methods, and the like.
The polymers of group (4) are polymers obtained by modification of single-terminal hydroxylation products of low molecular weight polyethylene, and for example, those prepared by chemical modification, such as Unilin (registered trademark), which are primary alcohols resulting from 80 to 85% modification of the terminals of polyethylene having up to 50 carbon atoms on the average, are known. However, their application fields are limited because the molecular weight of the starting material Unilin is limited to relatively low molecular weights, the type of polymer is limited to polyethylene, and the like.
Furthermore, it is known that highly functional, controlled polymers such as comb-like polymers can be obtained by copolymerizing polymers or oligomers that are polymerizable due to the presence of the introduced functional groups, as generally referred to as macromonomers, with other monomers. Many examples of the polymers having polyolefinic macromonomers as the component are known, but polyolefinic macromonomers having polymerizable unsaturated groups have smaller amounts of polar groups and are difficult to be used for the purpose of modifying polyolefins. Other known polymers having polymerizable functional groups include a polymer having hydroxyl groups at the terminals (JP-A No. 9-3173), and a polymer having epoxy groups within the polyolefin chains (JP-A No. 4-55403); however, since the former is rendered polymerizable by further reacting with a tetracarboxylic acid, the polymers obtained by using this macromonomer have limited structures. The latter has a plurality of alkylene oxides having a statistic distribution in one polyolefin chain, and thus there occur problems such as that crosslinking takes place during the reaction of alkylene oxide. Therefore, it is difficult to obtain a polymer having a structure comprising a controlled polyolefin skeleton and a skeleton containing polar groups, by effectively utilizing the latter polymer as the macromonomer.    [Patent Document 1] JP-B No. 7-78098    [Patent Document 2] JP-B No. 7-91338    [Patent Document 3] JP-B No. 7-103181    [Patent Document 4] U.S. Pat. No. 5,252,677    [Patent Document 5] JP-A No. 2001-2731    [Patent Document 6] JP-A No. 2003-73412    [Patent Document 7] JP-A No. 1-217007    [Patent Document 8] JP-A No. 9-3173    [Patent Document 9] JP-A No. 4-55403